If you don't remember your password, you can reset it by entering your email address and clicking the Reset Password button. You will then receive an email that contains a secure link for resetting your password
If the address matches a valid account an email will be sent to __email__ with instructions for resetting your password
This study aimed to investigate the effect of preoperative oral carbohydrate (POC) loading on the occurrence of complications in the postanesthesia care unit (PACU) after general anesthesia.
Design
Prospective observational cohort study
Methods
Patients who were scheduled for abdominal surgery under general anesthesia at our institution were divided into the POC group and control group based on whether they drank carbohydrate solution 2 hours before surgery. POC loading of the patients was decided by the responsible surgeon. In PACU, the occurrence of postoperative complications including delayed emergence, emergence agitation, hypoxemia, hypertension, hypotension, moderate to severe postoperative pain, nausea and vomiting, hypothermia, shivering, and time to awakening, time to extubation, length of PACU stay were recorded.
Findings
Data from 307 patients (n = 154 in POC group and n = 153 in control group) were included in the final analysis. Compared to the control group, POC led to a near-significant reduction in the overall incidence of complications in PACU after surgery (37.0% vs 47.7%, P = .058). The POC group had a lower incidence of hypothermia and shorter mean time to awakening when compared to control group (6.5% vs 16.3%, P = .007 and 19 min vs 21 min, P = .007, respectively). No statistical differences were detected in other outcome measurements between the POC group and the control group.
Conclusions
POC is associated with a trend to decrease the overall incidence of complications during recovery period after general anesthesia in patients who underwent abdominal surgery. Moreover, POC could reduce the risk of hypothermia in PACU and shorten the time to awakening.
Despite the great advancements in perioperative management, complications in the PACU remain common. The reported overall incidence of postoperative complications in PACU, including desaturation, excessive pain, agitation, delayed recovery, shivering, hypothermia, nausea/vomiting, hypertension, hypotension, and others, was as high as 23.7%-39.9%.
Incidence of complications in the post-anesthesia care unit and associated healthcare utilization in patients undergoing non-cardiac surgery requiring neuromuscular blockade 2005-2013: a single center study.
As postoperative complications require a more intense level of care and prolonged length of stay in PACU, and thus increase health care resource utilization,
However, a general consensus has been developed that this traditional practice is out of date and is associated with postoperative complications including insulin resistance and metabolic disorders.
American Society of Anesthesiologists C Practice guidelines for preoperative fasting and the use of pharmacologic agents to reduce the risk of pulmonary aspiration: application to healthy patients undergoing elective procedures: an updated report by the American Society of Anesthesiologists Committee on standards and practice parameters.
Current evidence indicates that oral intake of clear liquids up to 2 hours before surgery is safe, and preoperative oral carbohydrate (POC) loading does not delay gastric emptying or influence gastric acidity.
Practice guidelines for preoperative fasting and the use of pharmacologic agents to reduce the risk of pulmonary aspiration: application to healthy patients undergoing elective procedures: an updated report by the American Society of Anesthesiologists Task Force on preoperative fasting and the use of pharmacologic agents to reduce the risk of pulmonary aspiration.
Moreover, POC has been found to reduce insulin resistance, enhance recovery of bowel function and improve postoperative discomfort of surgical patients when compared to standard preoperative fasting.
It is still not known whether POC could reduce the incidence of complication during recovery period after general anesthesia. Therefore, this prospective cohort study aimed to explore the effect of POC loading 2 hours prior to surgery on the prevalence of complications in PACU in patients receiving abdominal surgery under general anesthesia.
Methods
Participants and Study Design
This study was approved by the hospital Ethics Committee and registered in Chinese Clinical Trial Registry (No. ChiCTR2000038157). All participants provided written informed consents.
The patients who were scheduled for open or laparoscopic abdominal surgery for gastrointestinal tract or gynecological diseases under general anesthesia in one hospital from October 2020 to May 2021 were recruited. Inclusion criteria were age 18 years and older, American Society of Anesthesiologists (ASA) physical status of I-III, surgery scheduled in the morning between 08:00 a.m. And 10:00 a.m. Exclusion criteria were metabolic and endocrine disease, body mass index (BMI) below 18 and above 28, fever, infection, psychiatric disorder, delayed gastric emptying (gastroesophageal reflux disease, gastroparesis, pyloric obstruction, pregnancy, opioid use). Patient's administration of oral carbohydrate solution 2 hours before surgery was decided by the responsible surgeon who did not participate in this study. According to whether they drank oral carbohydrate solution before surgery, patients were divided into POC group and control group.
The patients in POC group received 355 mL oral carbohydrate solution (Outfast, 355 mL/bottle, maltodextrin 10 g/100 mL, fructose 2.4 g/100 mL, glucose 1.7 g/100 mL, taurine, energy 241 KJ/100 mL; Humanwell Health care, China) 2 hours prior to surgery. In the control group, oral intake was restricted from midnight the day before the surgery.
Anesthesia Management
The temperature of the operating room was maintained at 20-23°C.The patients were covered with blankets after they entered the room. None of the patients received any premedication. Vital signs including heart rate (HR), electrocardiogram (ECG), non-invasive blood pressure (NIBP), pulse oxygen saturation (SpO2) were monitored by Mindray monitor (IPM5, Mindray Medical, China) and were recorded every 5 min throughout the surgery. Radial artery cannulation for biochemistry analyses was performed following anesthesia induction based on the responsible anesthesiologist's preference. Anesthesia was induced by intravenous injection of midazolam 0.02-0.05 mg/Kg−1, sufentanil 0.3-0.5 mcg/Kg−1, propofol 1.5-2.0 mg/Kg−1, and rocuronium 0.6-0.9 mg/Kg−1. After endotracheal intubation, mechanical ventilation was initiated to maintain pressure of end-tidal carbon dioxide of 35-45mmHg. Between the endotracheal tube and Y-connector of the respiration system, an artificial humidifier was used to humidify inhaled air. Nasopharyngeal temperature was continuously monitored with temperature probe of Mindray monitor (IPM5, Mindray Medical, China) for all of the patients after intubation. Sevoflurane inhalation in 50% O2 was administered for anesthesia maintenance. Sufentanil and rocuronium were injected intermittently when required. Bilateral transversus abdominis plane block (TAPB) was performed under the guidance of ultrasound at the discretion of the responsible anesthesiologist after anesthesia induction. Patients were administered heated (38°C) intravenous fluids during the operation. At the end of the operation, parecoxib sodium 40 mg and ondansetron 4 mg were injected intravenously to prevent postoperative acute pain and nausea and vomiting, respectively.
All patients were transferred to the PACU immediately after the operation. Patients were covered with blankets in PACU. HR, NIBP, SpO2, and ECG were monitored and recorded every 5 min. An infrared tympanic membrane thermometer (Thermo Scan PRO4000, BraunGmbH, Germany) was used to measure temperature every 10 min. Intravenous tramadol was administered through a patient-controlled analgesia (PCA) infusion pump (Rythmic Evolution, Micrel, Greece) to control postoperative pain on PACU arrival. Neuromuscular blocks were reversed by administration of neostigmine and atropine. Patients were extubated when laryngeal reflexes and spontaneous respiration recovered sufficiently. After extubation, 3-4 L/min O2 was given through face mask. Recovery of the patients was assessed using the Steward score: (1) awake 2 scores for fully awake, 1 score for arousable, 0 score for not responding; (2) ventilation 2 scores for being able to cough or cry, 1 score for breathing easily, 0 score for airway requiring attention; (3) movement 2 scores for moving purposefully, 1 score for moving involuntarily, 0 score for not moving.
Patients with Steward score of four and above were delivered to the surgical ward or intensive care unit (ICU).
Data Collection and Outcome Measurement
One authorized investigator who was blinded to the group assignments was responsible for the data collection and outcome assessment. Before and during the operation, information regarding age, gender, BMI, ASA physical status, surgical type, surgical approach, anesthesia technique, surgical duration, volume of intraoperative fluid infusion, blood loss volume and urine output volume were collected. After surgery, data on the occurrence of complications in PACU (delayed emergence, emergence agitation, hypoxemia, hypertension, hypotension, moderate to severe postoperative pain, nausea and vomiting, hypothermia, shivering), time to awakening (the time from the cessation of anesthetics up to the patients’ active reaction to verbal commands), time to extubation (the time from the cessation of anesthetics to extubation), and length of PACU stay were recorded.
Delayed emergence was defined as awakening time more than 30 min after discontinuing anesthetics. Emergence agitation was assessed with Riker Sedation-Agitation Scale
and a score of greater than or equal to 5 was diagnosed as emergence agitation. Hypoxemia was defined as SpO2 leaas than 90% for more than 30 seconds despite receiving supplemental oxygen. Hypertension was defined as systolic blood pressure (SBP) greater than 160 mmHg or increase greater than 20% of the baseline value for at least 5min. Hypotension was defined as SBP less than 90 mmHg or decrease greater than 20% of the baseline value for at least 5min. Postoperative pain was evaluated by the numerical rating scale (NRS) scored between 0 (no pain) and 10 (worst pain). Moderate to severe postoperative pain was defined as a NRS score greater than 3. Nausea was defined as a desire to vomit. Vomiting was defined as forceful expulsion of gastrointestinal contents through mouth. Hypothermia was defined as tympanic membrane temperature below 36°C at any time during the recovery period. Shivering was graded with Crossley and Mahajan scale: grade 0 = no shivering; grade 1 = piloerection or peripheral vasoconstriction without visible shivering; grade 2 = muscular contraction confined to one muscle group; grade 3 = muscular contraction involving more than one muscle group but not generalized; grade 4 = shivering involving the whole body.
Shivering was diagnosed when the grade was equal to or greater than grade 2. The complications were treated accordingly at the discretion of the responsible anesthesiologist in PACU.
The primary outcome measurement was the overall incidence of complications in PACU which was defined as the proportion of patients who developed at least 1of the above-mentioned complications in PACU. The second outcome measurements were time to awakening, time to extubation, and length of PACU stay.
Statistical Analysis
As previous studies reported that the incidence of complications during recovery period after general anesthesia was around 35%,
Incidence of complications in the post-anesthesia care unit and associated healthcare utilization in patients undergoing non-cardiac surgery requiring neuromuscular blockade 2005-2013: a single center study.
we determined that 138 cases in each group were needed to detect a 15% decrease in POC group when power = 0.80 and α = 0.05. Quantitative variables were presented as mean (standard deviation) or median (interquartile range) based on data distribution. And t test or Wilcoxon test was used for comparison between the groups accordingly. Qualitative variables were presented as number (proportion) and Pearson's χ2 test or Fisher exact test was used for comparison between the groups. The Statistical analyses were performed with SPSS, (version 26.0). P -value of < .05 (two-tailed) was considered statistically significant.
Results
A total of 386 patients scheduled for abdominal surgery were screened for eligibility. Of those, 11 patients declined to participate, 41 were excluded according to exclusion criteria, and 21 surgeries were canceled. Thus 313 patients were included (157 cases in the POC group and 156 cases in the control group, respectively). After surgery, 3 patients of each group were not admitted to PACU. As a result, 154 patients in the POC group and 153 patients in the control group completed assessment in PACU and were included in final analysis (Figure 1).
Figure 1Flowchart of participants throughout the study. PACU, postanesthesia care unit.
As Table 1 showed, no statistical differences were detected in the demographic characteristics, surgical and analgesia variables between the two groups (P > .05).
Table 1Demographic Characteristics, Surgical and Analgesia Variables in the Two Groups (N = 307)
Variables
POC Group (n = 154)
Control Group (n = 153)
P-value
Age (y)
55 ± 14
53 ± 13
.183
Gender (female/male)
126/28
124/29
.862
BMI (Kg/m2)
22.9 ± 2.9
23.0 ± 2.6
.784
ASA physical status (Ⅰ/Ⅱ/Ⅲ)
55/69/30
59/59/35
.684
Surgical type (gastrointestinal/gynecological)
58/96
48/105
.558
Surgical approach (open/laparoscopic)
26/128
25/128
.898
Anesthesia technique (general/general + TAPB)
129/25
138/15
.094
Duration of surgery (min)
150 ± 45
143 ± 46
.175
Intraoperative fluid infusion (mL)
1258 ± 389
1260 ± 377
.957
Urine output (mL)
200 (100, 300)
200 (100, 400)
.669
Blood loss (mL)
50 (30, 100)
50 (20, 100)
.601
POC, preoperative oral carbohydrate; BMI, body mass index; ASA, American society of Anesthesiologists; TAPB, transversus abdominis plane block.
Data are presented as mean ± standard deviation or medians (interquartile range) or numbers.
As presented in Table 2, compared to fasting overnight before surgery, POC led to a near-significant reduction in the overall incidence of complications in PACU after abdominal surgery (37.0% v. 47.7%, P = .058). Moreover, the incidence of hypothermia was lower during the recovery period in POC group than that in control group (6.5% vs 16.3%, P = .007). The mean time to awakening in POC group was shorter compared to control group (19 min vs 21 min, P = .007). Both time to extubation and length of PACU stay were similar between the groups (P > .05).
Table 2Incidence of Complications in PACU, Time to Awakening, Time to Extubation and Length of PACU Stay in the Two Groups (N = 307)
Variables
POC Group (n = 154)
Control Group (n = 153)
P -value
Delayed emergence
2 (1.3)
8 (5.2)
.106
Emergence agitation
31 (20.1)
32 (20.9)
.865
Hypoxemia
4 (2.6)
6 (3.9)
.740
Hypertension
9 (5.8)
9 (5.9)
.989
Hypotension
2 (1.3)
2 (1.3)
.995
Moderate to severe postoperative pain
13 (8.4)
8 (5.2)
.265
Nausea and vomiting
7 (4.5)
8 (5.2)
.781
Hypothermia
10 (6.5)
25 (16.3)
.007
Shivering
2 (1.3)
4 (2.6)
.674
Overall incidence of complications
57 (37.0)
73 (47.7)
.058
Time to awakening (min)
19 ± 4
21 ± 6
.007
Time to extubation (min)
23 ± 7
24 ± 8
.218
Length of PACU stay (min)
41 ± 10
43 ± 12
.140
PACU, postanesthesia care unit; POC, preoperative oral carbohydrate.
Data are presented as numbers (proportions) or mean ± standard deviation.
Early postoperative complications are frequent during the recovery period after general anesthesia. This prospective cohort study found that POC was associated with a near-significant decrease in the overall incidence of complications during recovery period after general anesthesia in patients who underwent abdominal surgery. It has been reported that POC administration resulted in improvement in the well-being of surgical patients in terms of thirst and anxiety, significant reduction in both postoperative metabolic and inflammatory response, and early recovery after surgery.
Effects of preoperative oral single-dose and double-dose carbohydrates on insulin resistance in patients undergoing gastrectomy: a prospective randomized controlled trial.
Effects of preoperative oral carbohydrate administration combined with postoperative early oral intake in elderly patients undergoing hepatectomy with acute-phase inflammation and subjective symptom burden: a prospective randomized controlled study.
As little is known about the effect of POC on complications in PACU, our study helps fill the gap of information. Given that we only found POC had a trend to decrease the overall incidence of complications during recovery period, further studies with larger samples are required to verify our findings. Furthermore, future research should aim to determine optimize type, dose and timing of preoperative carbohydrate loading. Additionally, patients with diabetes should be included in future trials so that research findings could be generalized to a wider group of patients.
In our study, hypothermia occurred in 11.4% of all patients during the recovery period of general anesthesia. The reported incidence of postoperative hypothermia in previous reports ranged from 4% to 90%.
The variation across studies might attribute to different definition of hypothermia, different measurement site, different thermometer devices, different surgical type and varying anesthesia management. The present study suggested that POC was associated with a reduction in the incidence of postoperative hypothermia in PACU. A previous study conducted in patients undergoing elective cesarean section demonstrated that POC loading led to a smaller decrease in core body temperature(0.3℃ vs 0.73℃, P = .01)during combined spinal-epidural anesthesia(CSEA) than those who fasted overnight.
Yatabe et al. found that the rats receiving 8ml/kg or 21ml/kg of carbohydrate rich beverage via an oral tube 30 min before general anesthesia induction showed a smaller reduction in core temperature from the baseline value compared to those receiving 8mL/kg of normal saline.
In one study, fructose solution infusion was administered at 0.5 g·Kg−1·h−1 from 3 hours before anesthesia induction to 1 hour following anesthesia induction, and the temperature of patients was higher than that of control group between 20 and 180 minutes after induction.
Another study showed that infusion of amino acids of 2 mL·Kg−1·h−1 for 2 hours prior to anesthesia reduced the risk of hypothermia during spinal anesthesia.
In our study, the ingredients of the oral carbohydrate fluid including maltodextrin, fructose, glucose, and taurine are effective nutrients to maintain body temperature.
In this study, time to awakening of the patients in POC group was statistically significantly shorter than that in control group. Hypothermia might decrease cardiac output, thereby impaired circulatory stability and drug pharmacokinetics, and finally resulted in prolonged action duration of opioids and delayed postoperative recovery.
It is possible that the shorter time to awakening in patients receiving POC may be related to the lower incidence of hypothermia in this group.
The present study has some limitations. First, in this observational study, the administration of POC of the patients was based on surgeons’ preference. Second, both gastrointestinal and gynecological procedures were not performed by the same surgeon, which might lead to possible result bias. Finally, all our results were from cases at a single institution, which limits the generalization of the conclusion. Therefore, randomized controlled trials (RCTs) with multicenter data should be conducted to confirm the role of POC in the prevention of complications in PACU after general anesthesia.
Conclusion
POC is associated with a trend to decrease the overall incidence of complications during the recovery period after general anesthesia in patients who underwent abdominal surgery. Moreover, POC could reduce the risk of hypothermia in PACU and shorten the time to awakening.
Incidence of complications in the post-anesthesia care unit and associated healthcare utilization in patients undergoing non-cardiac surgery requiring neuromuscular blockade 2005-2013: a single center study.
Practice guidelines for preoperative fasting and the use of pharmacologic agents to reduce the risk of pulmonary aspiration: application to healthy patients undergoing elective procedures: an updated report by the American Society of Anesthesiologists Committee on standards and practice parameters.
Practice guidelines for preoperative fasting and the use of pharmacologic agents to reduce the risk of pulmonary aspiration: application to healthy patients undergoing elective procedures: an updated report by the American Society of Anesthesiologists Task Force on preoperative fasting and the use of pharmacologic agents to reduce the risk of pulmonary aspiration.
Effects of preoperative oral single-dose and double-dose carbohydrates on insulin resistance in patients undergoing gastrectomy: a prospective randomized controlled trial.
Effects of preoperative oral carbohydrate administration combined with postoperative early oral intake in elderly patients undergoing hepatectomy with acute-phase inflammation and subjective symptom burden: a prospective randomized controlled study.
00223-4&id=gr1.jpg){kind=link}